I own it and it's my most versatile piece of equipment, built like a tank too. Use a chair and forced negatives to get you going for your first pullups/chinups. Then load a backpack with rocks and/or sand in plastic sandwich baggies to add resistance. You can also use it for beginner dips by putting it on the floor upside down. Same goes for pushups to keep your wrists from getting jacked up. And as stated before, start with just body weight and add resistance if you want.

Jogging and/or walking and/or bicycling are musts for cardio.

As for eating at restaurants, I shoot for whole grains or salads and if you ask nicely they'll usually hold fats and add protein like beans and sometimes tofu.

If you are going to do bodyweight stuff, I recommend high volume. If you struggle with high volume of reps pet set, then do low reps per set, but then do a high volume of sets. So for instance if your absolute max for press ups is say 15, then do sets of 10, and do as many as you can. That way you could easily do 100. Where as if you keep pushing to your limit, then you will struggle in each subsequent set.